His departure in mid-term — his current six-year term expires at the end of 2014 — underlines how the Texan notion that judges should be elected and not appointed is that way more in theory than in practice.

Texas justices, and judges, fill elective offices. But if there is a vacancy, the governor appoints a replacement to serve until the next election.

It has been a sort of unspoken tradition for Supreme Court justices to retire between elections. This may be partly because they think the governor is better suited to choose their replacement than the public.

(Stop right here and write down the names of as many Supreme Court justices as you can. If you reach three, you are paying close attention. If you hit six, you are an expert. If you get all nine, you are either a Republican election junkie or a lawyer who practices before the court.)

Early retirement is probably nudged along by the fact that most justices can make a lot more bucks in private law practice after being on the high court, rather than staying there. A pay hike Sept. 1 raised annual salaries for justices to $168,000, and $170,500 for the chief justice.

Jefferson says money is why he’s quitting — one son in college, a second about to be, and a third in eighth grade.

Rick Perry moved from lieutenant governor to governor on Dec. 21, 2000, after Gov. George W. Bush resigned to move to the White House after the U.S. Supreme Court confirmed his election.

Of the 15 justices who have come to the high court since, Perry appointed 11. Only four first got there by election.

When Jefferson said he was retiring, Perry picked Justice Nathan Hecht, the court’s most senior justice, now in his 25th year, to move up to chief. Hecht, elected in 1988, is in his 25th year as a justice.

(Hecht and all other justices mentioned here are Republican, unless otherwise noted.)

Perry’s replacement in Place 8 for Hecht will be his 12th appointee.

Two other justices first got there by election: John Paul Devine, in 2012, and Paul W. Green, in 2004, re-elected in 2010.

The other six — two-thirds of the “elective” court — first got there by appointment of Perry, including Jefferson, Perry’s very first appointee to the state’s highest civil court, on April 18, 2001.

Jefferson replaced Alberto R. Gonzales, Bush’s former general counsel. Bush had appointed Gonzales to the bench Jan. 14, 1999, and he won a six-year term Nov. 7, 2000.

But he resigned Dec. 22, 2000, to go to the White House as the new President Bush’s general counsel.

In addition to Devine and Green, just two other justices got to the court through election since Perry has been governor.

Dale Wainwright was elected in 2002, replacing Deborah Hankinson, the rare modern justice — initially appointed by Bush — who served out her term. Wainwright resigned Sept. 30, 2012, to return to private practice.

The only other Perry appointee who lost his seat by election was also Hispanic: David Medina. Perry appointed him to the bench on Nov. 10, 2004.

Hispanics have sometimes had rough sledding in Republican primaries.

Medina won a full term in 2006. He was unopposed in the GOP primary, and got 75.5 percent against a Libertarian in the November election.

But in 2012, two Anglos challenged him in the primary — Joe Pool Jr. and Devine. Medina led the first primary, 39 percent to 32.2 percent for Devine and 28.8 percent for Pool. But Devine beat Medina in the runoff, with 53.3 percent.